Inflatable packer

ABSTRACT

An elongated tubular body connected with a well string in a borehole telescopically receives a centrally bored mandrel having means forming pistons slidable in fluid containing reservoirs formed between the wall of the body and one end portion of the mandrel. A dilatable and collapsible member surrounding and connected to the body intermediate its ends defines an inflation chamber communicating with the fluid reservoirs. Spring means, surrounding the tubular mandrel, normally urges the mandrel and body in telescopic extended relation.

United States Patent Shillander [451 Sept. 12, 1972 [54] INFLATABLE PACKER [72] Inventor: Harold E. Shillander, 4 Plaza Escalante, 414% Central S.E., Albuquerque, N. Mex. 87101 [22] Filed: April 5, 1971 [21] Appl. No.: 131,305

Related US. Application Data [63] Continuation-impart of Ser. No. 847,060, Aug.

4, 1969, Pat. No. 3,575,238.

[52] US. Cl ..166/187, 166/196 [51] Int. Cl. ..E21b 33/127 [58] Field of Search ..166/187, 196

[56] References Cited UNITED STATES PATENTS 2,942,669 6/1960 Mounce et al ..166/187 3,032,116 5/1962 Barry H ..166/187 3,104,717 9/1963 Sandlin et al ..166/187 3,575,237 4/1971 Malone ..166/187 3,575,238 4/1971 Shillander ..166/187 Primary Examiner-James A. Leppink Att0rneyRobert K. Rhea {5 7] ABSTRACT An elongated tubular body connected with a well string in a borehole telescopically receives a centrally bored mandrel having means forming pistons slidable in fluid containing reservoirs formed between the wall of the body and one end portion of the mandrel. A dilatable and collapsible member surrounding and connected to the body intermediate its ends defines an inflation chamber communicating with the fluid reservoirs. Spring means, surrounding the tubular mandrel, normally urges the mandrel and body in telescopic extended relation.

2 Claims, 5 Drawing Figures PATENTEDSEP 12 1912 3. 690,3 75

HAROLD E. SI-HLLANDER INVENTOI? CROSS REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of an application filed by me in the U.S. Pat. Off. on Aug. 4, 1969, under Ser. No. 847,060 for Inflatable Packer now U.S. Pat. No. 3,575,238.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to inflatable devices and more particularly to an inflatable packer for oil wells, or the like.

Inflatable packers are used in the oil well industry for forming a seal between the pipe string and wall of the casing or borehole to seal off formation zones and for various other purposes well understood in the oil industry.

The principal advantage of the inflatable packer over a conventional solid rubber or resilient material type packer is the ability to expand to a relatively larger diameter; form a seal with an irregular borehole wall surface; and withstand higher pressure differential without a flowing of the packer material.

2. Descripton of the Prior Art Some of the inflatable packers, as shown by the prior art, utilize fluid in the well inside or outside of the well string or within the casing to inflate the packer. This is accomplished by interrupting the circulation of fluid through the well string to build up a differentialpressure by a pump at the earths surface so that a valve, closed, as for example, by dropping a ball down the well string, actuates the packer for inflation by the fluid.

Other prior art packers employ a downhole hydraulic pump having an independent reservoir of fluid wherein the pump is actuated for expanding the packer by manipulating the pipe string. However, these independent fluid reservoir inflation packers frequently contain an insufficient volume of fluid for expanding a packer element into sealing relation with the irregular wall of a borehole. Q

.The most pertinent prior U.S. Pat. is No. 2,942,669 which discloses a valve means interposed in a fluid passageway providing communication between a fluid reservoir and a packer element for controlling the volume of fluid applied to the packer element.

The principal distinction of this invention over this patent is the elimination of valve means between fluid chambers of the patent by providing continuous communication between a primary reservoir and the packer element. This invention is further distinctive over the above patent and the invention of the copending application by a floating piston in the primary reservoir and the provision of a secondary or reserve reservoir communicating with the primary reservoir without increasing the overall length of the packer which permits necessary longitudinal movement of the packer element, setting components, relative to each other, while performing other functions, without expanding or setting the packer element. The packer element expanding action is accomplished by longitudinal telescoping movement of the packer components operating a closed hydraulic system.

SUMMARY OF THE INVENTION An elongated sleeve-like body is connected with a well string in a borehole. An elongated tubular mandrel is slidably received by and is secured within the body. A ring, slidably surrounding the mandrel, forms a floating piston slidable between the upper and lower limits of a fluid containing primary reservoir formed between an end portion of the body wall and the mandrel. An auxiliary or secondary reservoir is formed between the body and the mandrel at the body end portion opposite the floating piston and communicates with the primary reservoir. A dilatable member longitudinally surrounds and is connected with a portion of the body to form an inflation chamber communicating with the primary reservoir. Shoulders on the mandrel, on opposite sides of thefloating piston, respectively, move the latter for expanding and contracting the packer element. Spring means surrounds the mandrel below the body and normally urges the mandrel and body in extended telescopic relation.

The principal object of this invention is to provide an inflatable packer for connection with a well string in a borehole and having piston and reservoir means ar ranged in compact relation for expanding and collapsing the packer element by telescopic movement of the packer components.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view of the packer in collapsed position and connected with a fragment of a well string;

FIG. 2 is an elevational view of the packer element expanded against a'fragmentary portion of casing in a borehole;

FIG. 3 is a fragmentary elevational view, to a larger scale, partially in vertical section, illustrating the relationship of the components in packer element collapsed position;

FIG. 4 is a view similar to FIG. 3 illustrating the relationship of the components in packer element expanded position; and,

FIG. 5 is a horizontal cross-sectional view taken substantially along the line 55 of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT Like characters of reference designate like parts in those figures of the drawings in which they occur. In the drawings:

The reference numeral 10 indicates the device, as a whole, which is cylindrical in general configuration, adapted to be connected with a well string 12 and run into a borehole, indicated by the casing 14. The device 10 includes a sleeve-like body portion 16 threadedly connected at its upper end with a tool joint 18 in turn threadedly engaged with the well string 12. An elongated tubular mandrel 20 is telescopically received by its upper end portion by the inner wall surface 22 forming the bore of the body 16. The bore 24 of the mandrel 20 is slightly smaller than the bore, not shown, of the well string 12 and forms a continuation of the flow passage thereof. The depending end portion of the body is circumferentially enlarged to form a cylindrical wall portion 28 surrounding the mandrel 20 in spaced relation to form a fluid containing primary reservoir 30 and define an annular shoulder 32. Intermediate its ends a longitudinal portion of the mandrel 20 is diametrically reduced, as at 33, to form downwardly and upwardly facing shoulders 35 and 37, respectively, as viewed in the drawings. A ring member, rectangular in cross section in the example shown, forming parallel upper and lower end surfaces, surrounds the mandrel 20 between the shoulders 35 and 37 within the reservoir 30 and forms a floating piston 34 slidably contacting the reduced periphery of the mandrel and the inner surface of the wall 28. A lock-ring 36, loosely surrounding the mandrel, is threadedly engaged with the depending end of the wall 28 to maintain the piston within the body 16. As mentioned hereinabove the distance or spacing between the shoulders 35 and 37 is such that they permit a necessary amount of longitudinal movement of the mandrel 20 relative to the body 16,- as when indexing the well string, setting slips, or the like, without moving the piston 34 to set or release the packer as hereinafter explained.

A .dilatable and collapsible packer element 38, formed of reinforced resilient material, such as rubber, or the like, surrounds an intermediate portion of the body above its shoulder 32 and is secured thereto by inserting one end portion of the member 38 into an annular groove 40 formed in the shoulder 32. The other or upper end of the member 38 is similarly secured within an'annular groove 42 formed in a collar-like ring 44 slidably surrounding a'peripheral portion of the body 16 which compensates for longitudinal contractile action of the member 38. Any suitable conventional means may be used for maintaining the respective end portions of the member 38 within the grooves 40 and 42. The member 38 and the slidable ring 44, in combination with the body 16, forms an inflation or expansion chamber 46 which communicates with the primary reservoir 30 by a plurality of circumferentially spaced slots or wall ports 48 formed through the body shoulder 32.

The upper end 50 of the mandrel, when the mandrel is fully telescoped within the body 16, terminates slightly above the horizontal plane defined by the upper limit of the ring 44 and in downwardly spaced relation with respect to the depending end 52 of the tool joint 18. An upstanding pipe or tube 54 is threadedly connected, at its depending end, within the upper end portion of the mandrel 20 to form an extension of the mandrel and define an auxiliary or secondary reservoir 56 between the outer wall surface of the tube 54 and inner wall surface of the body 16 which is defined at its lower and upper limits, respectively, by the upper end 50 of the mandrel and depending 'end 52 of the tool joint 18.

' The periphery of the tube 54 is slidably received by the inner wall surface of the tool joint 18 and projects upwardly into the bore of the well string 12. The bore 58 of the tube 54 is diametrically equal to and forms a continuation of the mandrel bore 24.

Fluid communication between the primary or main reservoir 30 and secondary reservoir 56 is provided by forming a plurality, four in the example shown, of Iongitudinally extending channels or fluid passageways 60 between the upper end portion of the mandrel and inner wall surface of the upper end portion of the body 16. These passageways 60 are formed by subtending an are of the circumference of the mandrel, (FIG. 5). At least two of the passageways 60 extend downwardly coextensive with the upper shoulder 35 (FIG. 3) to provide constant communication between the reservoirs 30 and 56 while the other two passageways may terminate in selected spaced relation above the shoulder 35 (FIGS. 3 and 4). The reservoirs 30 and 56 and chamber 46 are filled with a selected fluid 62. The tube 54 thus forms a diametrically reduced upper end portion for the mandrel and the mandrel end 50 forms an annular shoulder which acts as a piston in forcing fluid out of the secondary reservoir for the purposes presently explained. Obviously the mandrel 20 and its extension tube 54 may be formed as a single unit, if desired.

The dimensions of the primary reservoir 30 and secondary reservoir 56, in combination with the chamber 46, when the packer element 38 is collapsed, are such that the volume of the fluid 62 contained therein will be substantially greater than the volume of fluid usually necessary to dilate the member 38 into sealing relation with the casing 14 or a borehole wall, not shown, for the purposes hereinafter explained.

Conventional seals, in the form of O-rings, are disposed in suitable grooves to form fluid tight seals for the inner and outer peripheries of the floating piston and between mating parts forming the reservoirs. The depending end portion of the mandrel 20 is provided with an enlarged tool joint-like portion defining an annular spring support shoulder 64. The depending surface of the lock-ring 36 is provided with an annular recess cooperatively nesting one end portion of a helical spring 66 loosely surrounding the depending end portion of the mandrel 20 between the shoulder 64 and the lock-ring 36. The purpose of the spring 66 is to normally maintain the mandrel and body in extended telescoped relation so that the packer element 38 will be normally maintained in its collapsed position, shown in FIGS. 1 and 3. The bore of the lock-ring 36 loosely surrounds the depending end portion of the mandrel below the shoulder 37 when the mandrel is telescoped into the body as explained hereinbelow. The depending end portion of the mandrel 20 is provided with tool joint threads 68 for connection with tube members 12A forming a part of or a continuation of the well string 12. The mating sliding surfaces of the mandrel 20 and body 16 may be splined or secured by keys to impart rotation to the mandrel and depending well string 12A about their vertical axis if desired.

OPERATION In operation the device 10 is run into a borehole or the casing 14 and is supported by the well string 12. The mass of the depending well string 12A, if used, normally maintains the packer member 38 in collapsed position, however, if the device 10 forms the terminal end portion of the well string the expansive action of the spring 66 in cooperation with the mass of the mandrel will maintain the packer element 38 in collapsed position. When it is desired to expand the packer element 38 into sealing relation with the casing 14 or a borehole wall the depending end portion of the well string 12A is set down on the bottom of the borehole, not shown. In the event the well string 12A is not used, the depending end of the mandrel, or a sub, not shown,

connected therewith, will be set down on a suitable bridge, not shown, formed in the casing or borehole. In either event lowering of the well string 12 telescopes the body 16 downwardly over the upper end portion of the mandrel 20 and its sleeve 54 thus moving the shoulder 37 into contact with the piston 34. The spring 66 is being compressed during this action and the fluid 62 within the primary reservoir is being forced by the piston 34 through the ports 48 and into the chamber 46 which forcibly distorts and dilates the packer element 38 into contact with the inner wall surface of the casing 14 or borehole thus forming a tight seal therewith. Simultaneously the movement of the tool joint end surface 52 toward the upper end 50 of the mandrel forces the fluid 62 out of the secondary chamber 56 and into the primary chamber 30 through the open passageways 60 thus supplementing the quantity of fluid available for expanding the packer to a greater diameter and insuring a seal with the wall of an uncased borehole. This setting down or pushing action of they body 16 over the mandrel 20 utilizes the mass of the well string 12 to increase hydraulic pressure into the chamber 46 in an efficient expanding action of the packer element 38. However, it seems obvious that the position of the reservoir 30 and chamber 46 may be inverted so that a lift or pull on the well string 12 would similarly force the fluid 62 out of the reservoirs 30 and 56 and into the chamber 46 to expand the member 38. To achieve this it would be necessary to use expandable slips connected with the well string portion 12A, which are normally set and released by a rotative action of the well string, to maintain the mandrel 20 rigid while the lift or pull action is performed. When it is desired to release the packer, the member 38 is collapsed by simply lifting the well string 12 wherein the body 16 longitudinally slides along the mandrel 20 until the shoulder contacts the piston 34 and moves it into contact with the lock-ring 36. This repositions the wall surfaces forming the reservoir 30 to the position shown by FIG. 3, wherein reduced pressure within the reservoirs 30 and 56 draws or pulls the fluid out of the chamber 46 to allow the resilient member 38 to return to its collapsed position. This packer setting and releasing action may be repeated as often as desired.

Repeated distortion of the member 38 may tend to prevent its returning to the desired position shown in FIG. 3, however, to more nearly achieve this action a helical spring, not shown, may be interposed in the chamber 46 to bear, respectively, against the adjacent surface of the shoulder 32 and sliding ring 44.

Obviously the invention is susceptible to changes or alterations without defeating its practicability, therefore, I do not wish to be confined to the preferred embodiment shown in the drawings and described herein.

lclaim:

1. An inflatable packer, comprising:

an elongated vertically disposed tubular body having a tool joint at its upper end adapted to be connected with a well string and lowered in a borehole;

a tubular mandrel telescopically received at its upper end portion by the inner wall surface of said body, one end portion of said body being circumferentially enlarged to define an outwardly projectin body shoulder and a cylindrical \y ill surroun mg an intermediate portion of san mandrel in spaced-apart relation forming a fluid containing primary reservoir between said body and said mandrel;

an annular ring forming a piston slidably interposed between the periphery of said mandrel and the inner surface of said cylindrical wall for movement toward and away from said body shoulder during telescopic movement of said mandrel into and out of said body;

oppositely facing shoulders formed on said mandrel in longitudinally spaced relation with respect to the respective opposing end surfaces of said piston;

tube slidably received within said tool joint and coaxially connected with the upper end portion of said mandrel and forming a fluid containing secondary reservoir between said body and said tube,

said mandrel haVing longitudinally extending fluid passageways formed in its periphery providing fluid communication between said reservoirs;

a lock-ring surrounding said mandrel between said oppositely facing shoulders and coaxially connected with the depending end portion of said cylindrical wall;

a cylindrical ring slidably surrounding the end portion of said body opposite said lock-ring; and, flexible and expandable cylindrical member longitudinally surrounding said body in circumferentially spaced relation and connected, at its respective end portions, with said body shoulder and said cylindrical ring for forming an inflation chamber,

said body shoulder having wall ports providing communication between the primary reservoir and the inflation chamber,

whereby fluid is forced from the reservoirs into the inflation chamber in response to telescopic movement of said mandrel into said body for expanding said flexible member into sealing relation with the wall defining the borehole.

2. The inflatable packer according to claim 1 in which the depending end portion of said mandrel is circumferentially enlarged to form a spring support shoulder facing toward said body, and,

a spring interposed between said spring support shoulder and said lock-ring for urging said body and said mandrel toward an extended telescopic relation. 

1. An inflatable packer, comprising: an elongated vertically disposed tubular body having a tool joint at its upper end adapted to be connected with a well string and lowered in a borehole; a tubular mandrel telescopically received at its upper end portion by the inner wall surface of said body, one end portion of said body being circumferentially enlarged to define an outwardly projecting body shoulder and a cylindrical wall surrounding an intermediate portion of said mandrel in spaced-apart relation forming a fluid containing primary reservoir between said body and said mandrel; an annular ring forming a piston slidably interposed between the periphery of said mandrel and the inner surface of said cylindrical wall for movement toward and away from said body shoulder during telescopic movement of said mandrel into and out of said body; oppositely facing shoulders formed on said mandrel in longitudinally spaced relation with respect to the respective opposing end surfaces of said piston; a tube slidably received within said tool joint and coaxially connected with the upper end portion of said mandrel and forming a fluid containing secondary reservoir between said body and said tube, said mandrel haVing longitudinally extending fluid passageways formed in its periphery providing fluid communication between said reservoirs; a lock-ring surrounding said mandrel between said oppositely facing shoulders and coaxially connected with the depending end portion of said cylindrical wall; a cylindrical ring slidably surrounding the end portion of said body opposite said lock-ring; and, a flexible and expandable cylindrical member longitudinally surrounding said body in circumferentially spaced relation and connected, at its respective end portions, with said body shoulder and said cylindrical ring for forming an inflation chamber, said body shoulder having wall ports providing communication between the primary reservoir and the inflation chamber, whereby fluid is forced from the reservoirs into the inflation chamber in response to telescopic movement of said mandrel into said body for expanding said flexible member into sealing relation with the wall defining the borehole.
 2. The inflatable packer according to claim 1 in which the depending end portion of said mandrel is circumferentially enlarged to form a spring support shoulder facing toward said body, and, a spring interposed between said spring support shoulder and said lock-ring for urging said body and said mandrel toward an extended telescopic relation. 